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Product Overview
Metric Grade 8.8 studs are high-strength carbon steel fasteners manufactured to ISO 898-1 and EN 14399 standards, designed for critical bolted connections in structural, automotive, and machinery applications. These studs are heat-treated to achieve a minimum tensile strength of 800 MPa and a yield strength of 640 MPa, making them suitable for high-load and dynamic environments.
Grade 8.8 is the most commonly specified class for metric threaded rods and double-ended studs, offering an optimal balance of strength, ductility, and cost-effectiveness. They are supplied plain, zinc-plated, or hot-dip galvanized for corrosion protection, and are widely used in steel construction, flange joints, and heavy equipment assembly.
| Material | Carbon Steel, Class 8.8 |
| UNS Number | K1045 (typical) |
| DIN Number | 1.1186 |
| Material Standard | ISO 898-1 |
| Stud Standard (Metric) | DIN 976 / DIN 939 / ISO 898-1 |
| Stud Standard (Inch) | BS 4439 / ASTM A193 B7 (for inch) |
| Thread Form | ISO Metric (Coarse & Fine) |
| Diameter Range | M6-M100 |
| Tensile Strength | 800 MPa (116 ksi) min |
| Yield Strength | 640 MPa (93 ksi) min |
| Hardness | Max 25 HRC / 255 HB |
Complete the Fastener Set
Technical Data
| Size (M) | Pitch (mm) | Thread Length (mm) | Min L (mm) | Max L (mm) |
|---|---|---|---|---|
| M6 | 1.0 | Full | 20 | 1000 |
| M8 | 1.25 | Full | 20 | 1500 |
| M10 | 1.5 | Full | 30 | 2000 |
| M12 | 1.75 | Full | 40 | 2000 |
| M16 | 2.0 | Full | 50 | 3000 |
| M20 | 2.5 | Full | 60 | 3000 |
| M24 | 3.0 | Full | 80 | 3000 |
| M30 | 3.5 | Full | 100 | 4000 |
| M36 | 4.0 | Full | 120 | 4000 |
| M42 | 4.5 | Full | 150 | 4000 |
| M48 | 5.0 | Full | 200 | 4000 |
| M56 | 5.5 | Full | 250 | 4000 |
| M64 | 6.0 | Full | 300 | 4000 |
| M72 | 6.0 | Full | 350 | 4000 |
| M80 | 6.0 | Full | 400 | 4000 |
| M100 | 6.0 | Full | 500 | 4000 |
| Standard | Covers | Thread |
|---|---|---|
| DIN 976 | Threaded rods & studs | Metric |
| DIN 939 | Double-ended studs | Metric |
| ISO 898-1 | Mechanical properties | Metric |
| EN 14399-4 | Structural bolting assemblies | Metric |
| BS 4439 | Inch threaded rods | Inch |
| ASTM A193 B7 | High tensile studs (inch) | UNC |
| Material Standard | Requirement |
|---|---|
| ISO 898-1 | Class 8.8 mechanical |
| EN 10204 3.1 | Mill test certificate |
| EN 10204 3.2 | TPI-witnessed MTC |
| ISO 4042 | Coating requirements |
Material Chemistry
| Element | Composition (%) |
|---|---|
| Carbon (C) | 0.25-0.55 |
| Manganese (Mn) | 0.50-1.65 |
| Phosphorus (P) | 0.035 max |
| Sulfur (S) | 0.035 max |
| Silicon (Si) | 0.15-0.35 |
| Chromium (Cr) | 0.30 max |
| Nickel (Ni) | 0.30 max |
| Boron (B) | 0.003 max |
Fastener Performance
| Stud Size | Dry (Nm) | Lubricated (Nm) | Clamp Load (kN) |
|---|---|---|---|
| M12 | 81 | 65 | 45 |
| M16 | 200 | 160 | 85 |
| M20 | 400 | 320 | 135 |
| M24 | 690 | 550 | 195 |
| M30 | 1350 | 1080 | 315 |
| M36 | 2350 | 1880 | 460 |
| M42 | 3700 | 2960 | 630 |
| M48 | 5400 | 4320 | 830 |
Industry Applications
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